Communication networks for switching and transmitting digitized voice information are usually formed by a plurality of communication systems partially connected to, or respectively meshed with one another and to which communication terminal equipment is connected. The call setup and the call control ensues with signaling information. The digitized voice information is communicated between the communication systems in message channels and the signaling information is communicated in a signaling channel of a multiplexed message stream. The digitized voice information usually exhibits a bit rate of 64 or 56 Kbit/s and the multiplexed message stream exhibits bit rates of n.times.64 Kbit/s (for example, 2048 Kbit/s), whereby the message streams between the communication systems are transmitted over non-switched transmission paths.
In order to more efficiently use the transmission paths and the transmission equipment arranged between the communication systems, compression devices allocated to the transmission equipment and are used to compress the digitized voice information (for example, to form a compressed voice information with 16 Kbit/s and then multiplexed to form a message stream of, for example, 2048 Kbit/s). The multiplexed message stream is demultiplexed and the compressed voice information is decompressed at a communication system receiving such a message stream. Given a connection to a destination communication terminal equipment of this destination communication system as may be set up by the signaling information, the decompressed voice information is further communicated to the respective destination communication terminal equipment.
German Published Application DE 44 23 792 A1, for example, discloses a circuit arrangement for multiple utilization of basic channels in ISDN. The total data bit rate of 64 Kbit/s, available in a basic channel of an ISDN connection for data transmission, is divided time-offset with a suitable converter onto a plurality of data-reduced or, respectively, compressed, voice-coded, multiplexed speech channels having a lower bit rate.
When the respective communication system, according to the connection that has been setup, represents a transit communication system, then the respective, decompressed voice information is switched connection-conforming and is subsequently compressed again, inserted into a message stream or, respectively, multiplexed and communicated to the further communication system in conformity with the connection. The decompressing and compressing in the transit communication system causes time delays and distortions of the voice information that lead to a deterioration in the quality of the communicated, digitized voice information.